A diagram of the male urinary bladder and urinary passage (i.e., the lower urinary tract) is presented in FIG. 1. The bladder 400 temporarily stores urine 410 and periodically expels it when the bladder neck 420 opens, as the bladder 400 contracts. Urine 410 passes through the prostatic urethra 430, which is completely surrounded by the prostate 440. The distal portion or segment of prostate 440 is marked by a small projection called the verumontanum 450. This is a important landmark because distal thereto, is the external urethral sphincter 460, which relaxes prior to the urination process beginning. Beyond this is the bulbous portion 465 of urethra 470, affording a free passage of urine 410 external to the body, beyond the external urethral meatus 480.
Presently, millions of men in the United States alone exhibit some form of lower urinary tract symptoms (LUTS), with bladder outlet obstruction (BOO) being a major subgroup of LUTS. BOO is primarily caused by the enlargement of the prostate gland (e.g., benign prostate hyperplasia (BHP)) which results in radial compression of the urethra surrounded thereby (i.e., the prostatic urethra), thus obstructing (i.e., constricting) urine flow, resulting in incomplete emptying of the bladder (i.e., there being what is clinically referred to as a “post void residual” (PVR) of urine remaining in the bladder). Persons exhibiting an abnormal PVR will often need to urinate more frequently, and are likely to experience other physical discomfort, such as frequent urges to urinate, and physical exhaustion due to sleep deprivation, a condition clinically referred to as nocturia.
In addition to being symptomatic of BOO, the inability to pass urine (i.e., retention) may also occur due to loss of bladder function, or a depletion of normal bladder function which occurs in harmony with increased prostatic urethral resistance. Retention may also occur due to treatment of the prostatic urethra which often times causes a temporary swelling of the urethra until healing is complete. Such treatment includes the current standard of care for an enlarged prostate, referred to as trans-urethral resection procedure (TUR or TURP). Other treatments include minimally invasive debulking procedures such as trans-urethral microwave thermal therapy (TUMT), trans-urethra needle ablation (TUNA), prostatic alcohol injections, and cryogenic treatments. Patients are often times chronically in retention while awaiting any of these, or other clinical procedures. Some men will go into acute retention following unrelated surgeries such as hip surgery.
Another population of patients who frequently experience retention are those who have undergone minimally invasive or invasive cancer treatments for the prostate. When cancer is treated in the prostate two common options are radical prostatectomy, and brachytherapy. While the former approach involves the complete excising of the prostate, the later involves the injection of seed material into the prostate which is radioactive or excited by radiation, and thusly intended to selectively kill the cancer cells.
Patients suffering from reduced urine flow, incomplete emptying of the bladder, small volume urination, or combinations thereof, often require some interventional means to periodically drain or augment drainage of the bladder. Medical intervention of retention may include pharmaceuticals, minimally invasive procedures, prostatic support device insertions to support the prostatic region, or surgical interventions. Failure to take action can result in over distention of the bladder, leading to damage of the epithelium and detrusor muscles associated with the bladder, and an increased potential for urine reflux and bacterial invasion into the kidneys which is commonly thought to contribute to life-threatening renal failure.
Presently, the Foley catheter is the most common standard of care for obstruction treatment. A Foley catheter may be fairly characterized as being a tube having a pair of lumens extending therethrough, one of the lumens being used for inflation of a “balloon” supported adjacent a free end thereof, and of a relatively smaller diameter than the other. The free end of the Foley catheter is received within the external urethral meatus, and fed through the urethra until the balloon is positioned in the bladder. Thereafter the balloon is filled with sterile saline so as to expand (i.e., increase volume). Having been filled with anywhere from about 4 to 10 cc volume, the Foley catheter is then retracted until the balloon comes into contact with the bladder outlet. The nurse or physician then knows that the device is properly placed by tactilely sensing the abutting engagement of the balloon with the bladder neck.
Although catheterization is widely used to drain the bladder, it is sometimes clinically more desirable to place an indwelling device to support the prostatic urethra to relieve retention, or an excessively severe obstruction. This too has its shortcomings.
It is generally believed that the current options for sizing prostatic support devices are more complex, costly, and invasive than is required for proper device selection. One sought after sizing measurement is readily ascertained by tactilely detecting the location of the bulbous urethra relative to the bladder outlet. As previously noted, the bladder outlet is tactilely located whenever a Foley catheter is properly deployed. For proper placement of an intraurethral support device so as to assure that the external sphincter is not held open, the distance from the bladder outlet to the external sphincter must be determined. This may be acquired easily due to the fact that there is a second convenient anatomical feature which may be detected during measurement. The external sphincter is located at the bladder side of the bulbous urethra. The bulbous urethra is a very pronounced anatomical feature in that there is considerable widening of the urethra in this region. If a sound (i.e., Bougie) or a catheter is introduced into the urethra and advanced, contact with the external sphincter is easily detected therewith (i.e., tactilely with the hand).
Beyond notions of intervention, in roads are presently being made in the area of office and office/home based monitoring of patients for purpose of diagnosing the contribution of the prostatic urethra to the outflow urodynamics. Differential diagnosis is understood by accepting that there are three primary anatomical organs which interact to contribute to the function of urination: first the bladder, second the urethra, and third the sphincters. As previously noted, the prostatic gland surrounds the urethra in the very short segment between the bladder, at its outlet, and the external sphincter.
As bladder outlet obstruction patients are a subgroup of patients with LUTS, proper treatment of the specific problem requires a knowledge of complete urodynamic status of the patient in order determine the cause of the symptoms. Causes may include bladder deficiencies such as bladder decompensation or hypertrophy, sphincter dysnergia, prostatic obstruction, urethral lesions and others.
There exist diagnostic procedures available to clinical urologists, the purpose of which is to assess the physiologic properties of the lower urinary tract and symptoms related thereto. Such tests, which address the filling/emptying conditions (i.e., dynamics) of the bladder, include, but are not limited to, the use of video fluoroscopy simultaneously with the holding and release of urine, cystometry, urethral pressure profiling, ultrasonic volume assessments, and uroflowmetry. In addition to the aforementioned utility of sizing prostatic support devices and the like, the subject invention provides additional heretofore unknown diagnostic options which allow for relatively simple and increased understanding of the urinary tract by assessing the elements (i.e., structures or architecture) thereof, more particularly the prostatic urethra and their influence on urine flows.